1. Field of the Invention
The present invention relates to an apparatus for detecting a load amount and a load compensation amount of an elevator and method thereof, and more particularly, to an apparatus for detecting a load amount and a load compensation amount which is capable of detecting a weight of a passengers in an elevator even through a load detector for detecting the weight of the passengers in the elevator does not have linear characteristics in proportion to the weight of the passengers, capable of detecting an accurate load compensation amount by controlling differently an initial starting torque of a drive motor depending on floors where an elevator car is positioned to thereby improve a ride comfort when the elevator car starts moving, and capable of improving a reliability for a basic data of an operation such as a situation analysis for the use of elevator such as detection of a full capacity of the passengers, computation of the number of the passengers in getting in and getting off by floors, to thereby improve an efficiency in service of the elevator and method thereof.
2. Description of the Background Art
FIG. 1 is schematic block diagram of an apparatus for detecting a load amount and a load compensation amount of an elevator in accordance with a conventional art.
As shown in the drawing, at the lower portion of the inside of the elevator car 1, there are provided a rubber isolator 2 of which displacement amount is varied according to weight of the passengers on the elevator, a load detector 3 for converting the displacement amount of the rubber isolator to an electric signal, and a position detector 9 for detecting a position of the elevator car 1.
An output signal of the load detector 3 is applied to the converter 4, and the converter 4 converts the analog signal of the load detector 3 to a digital signal and transmits it to the input unit 5.
The digital signal transmitted to the input unit 5 is transmitted to the CPU 8 where if there is no passenger in the elevator car 1, its percent load value for the passengers becomes 0% according to a load amount detecting operation expression and stored in the memory unit 6, while if there is passengers as much as the rated load amount, the percent load value is operated as 100% and stored in a specific region of the memory unit.
The percent load value for the passengers is read from the memory unit 6 as necessary, converted to a basic data for the operation control data and the torque signal of the drive motor by a predetermined operation expression, and then outputted through the output unit 7.
The operation of the apparatus for detecting the load amount and load compensation amount of an elevator in, accordance with the conventional art constructed as described above will now be explained.
First, an output data of the load detector 3 is set in a no-load state that load of the elevator car 1 is `0` and the current load amount of the passengers of the elevator is detected by using the output data of the load detector 3 in the full load state that the load of the elevator car 1 is a rated load on the assumption that the load detector 3 has a linear output characteristics for all load states.
FIG. 2 is an operation graph for detecting the percent load of the passengers of the elevator over the output data of the load detector 3, in which Y axis indicates a percent load of the elevator passengers, and X axis indicates the output data of the load detector 3. Here, Ya shows the case where there is no passengers in the elevator car 1, that is, a no-load state having 0 percent load value, and Xa indicates the output data of the load detector 3 in a no-load state. Yb shows the case where there is passengers in the elevator car 1 as much as the rated load amount, that is, a full load state having 100% load value. Xb indicates an output data of the load detector 3 in the full load state.
The point Q1 corresponding to the value in the no-load state, and the point A5 corresponding to the value in the full load state are set when the elevator is installed, and if an error occurs between the actual load amount and the load amount according to the load amount operation after the elevator is installed, they are re-set.
Detection of the load amount for the current elevator is computed by a linear function f(x) over the line linking the point Q1 and the point Q2. When the function f(x) is expressed by alx+a2, a slope a1 of f(x) has the value of (Yb-Ya)/(Xb-Xa), and a2 can be computed by using one value of the point Q1 and the point Q2. Thusly computed values are stored in the memory unit of FIG. 1 in the form as shown in FIG. 3.
FIG. 4 is a flow chart of a process of detecting a load amount according to the above method, which will now be described.
First, a detect value of the load detector is read through the input unit (stage: 410). In this respect, for example, the detect value is assumed as Xc. Thereafter, the coefficients a1 and a2 of f(x) of the memory unit are read (stage: 420). Assuming that a percent load value desired to be obtained is Yc, this value is computed as a1x+a2 (stage: 430). The computation result is transferred to the output unit (stage: 440).
The detection of the load amount will now be described with reference to FIG. 2.
In case that the value detected by the load detector is Xc, in order to obtain a percent load value, a vertical line is drawn from Xc to the straight line linking Q1 and Q2, which is met at the point Q3, from which a straight line is drawn to Y axis. Here, the point meeting with the Y axis, that is, Yc is the percent load value over the load state inside of the current elevator car.
Meanwhile, in controlling an initial starting torque of the drive motor so as to keep favorably the ride comfort when the elevator starts, a bias amount is respectively set according to the position region and the operation direction of the elevator car 1 in the no-load state, which is critical factor for the initial starting torque.
Operation expression of the initial starting torque of the driver motor is as follows: EQU Initial starting torque=(weight of the passengers x starting compensation gain)+bias amount (1)
In the above equation, the starting compensation gain refers to a compensation amount for the initial starting torque in a full load state, and the bias amount refers to a compensation amount for the initial starting torque in the no-load state, which has different values according to the operation direction and the position region of the elevator car 1
When the elevator car moves upward in a state that the initial starting torque is small for the passengers of the elevator car, the elevator car 1 starts moving upward with a downward slip, while when the elevator car 1 moves upward in a state that the initial starting torque is large for the passenger of the elevator car, a starting shock occurs so that the elevator car 1 moves at a pre-set speed after bouncing in the upward direction, which spoils the ride comfort.
FIG. 5 shows an up-bias amount of each position of the elevator car 1 when it moves in the upward direction, of which X axis indicates a bias amount and Y axis indicates a position of the elevator car 1. Here, the point R indicates an upbias amount set at the lowermost floor is the point R, the upbias amount set at the middle floor is the point S, and the upbias amount set at the uppermost floor is the point `T`.
The upbias amount by floors of the elevator car 1 is applied in a manner that the distance from the lowermost floor to the uppermost floor is divided into three parts of a low zone, a middle zone and a high zone so that if the elevator car 1 is positioned in the low zone, the upbias amount corresponding to the point R is applied thereto, if the elevator car 1 is positioned in the middle zone, the upbias amount corresponding to the point S is applied thereto, and if the elevator car 1 is positioned in the high zone, the upbias corresponding to the point T is applied thereto.
FIG. 6 is a flow chart of the upward operation in case that the bias amount by positions of the elevator is applied.
First, a value outputted from the elevator position detector is inputted through the input unit at stage 601.
And, it is judged whether the current operation direction of the elevator car is an upward direction. Here, it is assumed that the operation direction is the upward direction at stage 620.
Thereafter, it is judged whether the current position of the elevator car is in the high zone or in the middle zone at stages 630 and 640.
If it is judged that it is in the high zone, `T` value is read out from the memory unit 6, while if it is judged that it is in the middle zone, `S` value is read out from the memory unit at stages 660 and 670.
And then, the value as read is outputted to the output unit at stage 680.
If the current position of the elevator car does not correspond to the two zones, it is judged that it is positioned in the low zone, according to which a bias amount R is read out form the memory unit at stage 650 and then outputted to the output unit at stage 680.
A downbias amount in the downward direction is applied in the same manner that bias amounts by position zones and operation directions of the elevator car 1 are set when the elevator is initially installed. In this respect, if a stroke of the elevator is great, the bias amount by position zones is divided into three intervals, for which a bias amount is set and applied.
However, the conventional art has problems in that an error is contained in detecting the load amount due to the non-linearity of the output data of the load detector according to the load amount increase, which does not provided an accurate load amount. And, since the bias amount of the floor where the elevator car is actually positioned is not accurately detected in the operation process of the initial starting torque when the elevator car starts moving, so that an error occurs, making it impossible to compute an accurate starting torque